Crankcase Pressure/Evac System/Stage 6 Heads

Happy 4th everyone! I got thru the transmission puke issue and made it out to a test and tune only to run into my next gremlin. So picked up this 500 ci motor complete as a stroker and had machine shop go thru it to lower compression. In that process bored it over a little more and did 10/10 on rods and mains so motor is fresh. Rings were file fit per instructions with the pistons by the machine shop and this guy knows what he's doing, but I haven't done a leak down check or anything like that yet. Motor was being run with evac canisters on both valve covers, but I did change them out for new ones. Welded in the bungs into my collectors at the angle and depth that are on another pair of headers I have. But getting oil blowing out of my sheet metal valley pan that was with the motor when I bought it. This is only happening on a run, mainly. Originally was only from the rear, I put a valley pan bar on the rear. Made 3 passes and by third pass had to quit for the night as oil came out the front and the rear. So looking for a remedy on this. I do have 2 other sets of canisters I can try. Also curious what other guys are using for valley pan for Stage 6 heads. I think the spacer makes things difficult for any other valley pan from my thoughts. What things can I check with the canisters or anything else to figure this out before going with a vacuum pump?

Adding the reinforcement plates across the 3 hold down bolts on each end might stiffen it up enough to stop the leakage.

Are you using any type of sealer at the ends? I also would use the plates. Take off reseal put plates on and try again.

On my 383/496 motor with Stage VI heads, I use the pan evac from Moroso only. The diaphragm inside the breathers and check valve can get rusty and not work properly, you can put a vacuum gauge on the hose at the valve cover and check the amount of vacuum its actually pulling. I use the aluminum valley pan from Hughe's but have to trim to fit along with the front and rear support brackets, I do use Permatex Right stuff to seal all four contact area's, never had a leak making mid 9 seconds passes. I use a Edelbrock RB 440 intake with no spacers and that buys more room to use the aluminum valley pan.

I used the MP intake so no “pan” was required on our old RB/498 StgVI mill. It seemed fairly common for it to leak some oil on a pass, until its last freshen when we used Total Seal rings. Always used the Moroso breathers. Looking in the headers it appeared from some residue that it was pulling vapor from the crank case.

A good vacuum pump is your friend, 30 HP + gain above 6000 RPM and the oil stays clean a lot, lot longer

Yea, I had sealed the ends with the high pressure grey RTV that i used on my girdle. It blew thru on the back side first, did some silicone on the lip afterwards and added a valley tray bar, then it ended up coming out the front as well. They need resealed, but only after I figure out what the fix is, either bad check valves which are new at the headers, bad canisters on the valve covers which are new too. Or. . . scrap it all and do a vacuum pump. It's just that if I can fix it for $50 bucks, rather do that than a grand on the vacuum pump.

So I took the plunge and bought a vacuum pump kit from GZ Motorsports. Will be starting the install on it this weekend. Couple questions that come to mind, and no I haven't read all the paper work yet. It could be in there, but wanted to put this out to the group while it's on my mind. Looks like the pump is set for 21. What "pressure" does everyone else run there's at? Read somewhere to much can pull oil from the bearings. Also, do any of you mount a permanent gauge to monitor this? Big block chevy buddy tells me his is set to 15, and has a port in the fuel pump block off plate. Just trying to gather all info (and parts) ahead of time. Thanks!!!

Which GZ pump did you buy?
The pump may or may not be able to pull the vacuum you want, that depends on how good you have your motor sealed up on the rings and seals and gaskets and how tight you can get the drive belt, been there learned that
Good luck, do NOT put the vacuum fittings in the fuel pump block off plate You will fill the puke tank in one or two runs
My motors ended up liking the fitting in the top of the cast aluminum valve covers with no breather caps on them, I ended up buying some of the cast polished aluminum valve covers from either Speedmaster or Pro Form from Summit Racing that had no holes in them and drill them with a large Unibit bit to fit the rubber grommets I needed when I was using a PCV only and ended up buying another pair and bought a screw on two piece fitting that I could use a AN hose from the pump to that fitting only and did not put any other holes in them, I would disconnect that fitting when I would change oil and use a small funnel to pour the oil into the motor through that fitting
I didn't mount my pump on my front motor plate so I could tighten it or loosen it up Never again The most vacuum I could pull was right at 5.5 inches no matter what I did other than remounting the pump better, that was with the GZ enhanced pump, their best one
I have bought two Moroso vacuum pumps since then, one three vane and one four vane, I'm hoping they both work better, I'll really focus on sealing the motors better and mounting the pumps so they can be adjusted to tighten the belts really tight
Good luck on your deal

Cab, I bought the super pro pump. My motor is sealed up very well, other than this pesky deal at the sheet metal valley pan. The port I meant in the fuel pump block off plate is intended to leave a gauge, or hook up a gauge too. I will put the main line port in the top of the valve cover.

My GZ pump pulls about 19-12hg. It has a fitting in the valley plate for 1/4" pushlock to the vacuum gauge. It could be in the valve cover as well. My fitting is in the front wall of the valve cover close to the intake side. pulls about 3-4oz of oil in 20-25 passes.
Doug

Do you have any kind of baffle plate in the valve cover where the port is on the insdie? Or is it straight open into that area?

I had a baffle welded under my fittings on my cast aluminum valve covers that broke the welds off after a while, I don't know exactly when it did that, I found it when I went to check the valve lash and remove it and saw no difference in performance or oil in the catch can after removing it My message I don't think you really need one

I run a Moroso Advanced 4 Vane vac pump. No issues with it. 17-19". Only adds to the over flow with only a couple of oz after many passes and hundreds of street miles. I still drain it after ever pass just to be sure.

Well, the pump worked better than it's supposed to. Factory set for 21, it pulled that and more and sucked the valley pan down. GZ said factory set for 21 it would never pull that much on my motor, guess I have it sealed up pretty good. This was on the initial run to test and set it. So, gotta take the manifold back off, try to figure out what I can do for a valley pan and re set it. Plan for the next time is to back off the regulator and sneak up on it. These stage 6 heads seem to limit me on what I can do for a valley pan. No racing this weekend. . .

You should never start with it maxed out and work down. Always start low and work up. I can't believe they didn't tell you to do it that way.

Too much vacuum, supposedly pulls oil from the wrist pins on some setups. I pull 10 on mine. Went to 15 seen no improvement in ET. Went back to 10 and left it there.

Just open. No baffle.
Doug